This proposal addresses the development of a new radical tricyclization protocol which allows the simultaneous construction of three carbon- carbon bonds and three rings in one synthetic step leading to the synthesis of biologically active products. The mechanism for this transformation involves the conversion of enediynes into reactive biradical intermediates which can trap pendent acceptors in radical cyclization reactions. These biradicals are also known to possess DNA cleaving and anticancer activity and the present studies describe the discovery of a new class of potential DNA cleaving agents. Although these studies are significant to the understanding of the chemical behavior of these unique reactive species and to the development of efficient methods for the synthesis of multicyclic systems, the preliminary results and proposed studies are of importance to the health sciences field. The potential for efficient construction of complex ring systems should permit the synthesis of biologically important natural products such as anticancer, antibiotic, antiinflammatory and anti-AIDS agents in a minimum number of steps. The described methodology should also be applicable to various structural analogues of biologically active natural products. In addition, assays will be done to study the DNA cleaving activity of these compounds. these studies may yield useful data for enhancing the activity of these DNA cleaving agents and providing broader applications of enediynes as antitumor agents. Finally, the pursuit of the synthetic challenges described herein will serve to train organic chemists whose talents will be needed in the future as researchers in the pharmaceutical industry.